Currently, in view of global warming prevention, introduction of renewable energy generation systems is in progress in the global scale. In such a circumstance, wind power generation is one of power generation methods which are being popularized. However, in Japan, the popularization rate of windpower generation is low compared to that in Europe or the like.
The reason for the difficulty of popularization of wind power generation in Japan is largely because of its geographical constraints. In particular, in Japan, wind force and direction change rapidly due to the mountain climate, making it difficult to maintain stable outputs in wind power generation. Such factors cause decrease in power generation efficiency per windmill, and consequently raise introduction costs of wind power generation systems.
To introduce large-scale wind power generation in a region where a wind velocity and direction change rapidly like in Japan, it becomes necessary to develop windmills which are variation resistant and overcome these problems. Accordingly, there is proposed a wind power generation system in which an airflow generation device generating plasma induced flow by plasma generated by applying a voltage between electrodes disposed to face each other via a dielectric is disposed on a blade surface of a windmill, to thereby enable control corresponding to variation of wind.
In a wind power generation system, blades are frequently damaged by lightning strikes. Therefore, if airflow generation devices including metal electrodes are applied to blades of a windmill, a current of lightning passes through the metal electrodes at the time of the lightning strikes, which may possibly cause not only a breakage of the electrodes and a power supply but also a damage of blade bodies near the airflow generation devices. In order to apply the airflow generation devices to an actual windmill, it is necessary to establish a structure for preventing the airflow generation devices from receiving the lightning strike and preventing a large current from passing therethrough, and a method for implementing the structure.